Sub-second dynamics of theta-gamma coupling in hippocampal CA1

• Type of Material: Article
• Authors: Lu Zhang, Georgia Institute of Technology; John Lee, Georgia Institute of Technology; Christopher Rozell, Georgia Institute of Technology; Annabelle Singer, Emory University
• Language: English
• Date: 2019-07-29
• Publisher: eLife Sciences Publications
• Publication Version: Final Published Version
• Copyright Statement: © Zhang et al.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.7554/eLife.44320
• Title of Journal or Parent Work: eLife
• ISSN: 2050-084X
• Volume: 8
• Grant/Funding Information: David and Lucile Packard Foundation to Annabelle C Singer; National Institutes of Health R01 NS109226 to Annabelle C Singer.; National Science Foundation CCF-1409422 to Christopher Rozell.; DSO National Laboratories - Singapore to John Lee.
• Keywords: PHASE PRECESSION; PATH-INTEGRATION; MEMORY CONSOLIDATION; ENSEMBLE ACTIVITY; TIME CELLS; OSCILLATIONS; SPATIAL REPRESENTATION; Life Sciences & Biomedicine; PYRAMIDAL CELLS; Science & Technology; PLACE CELLS; Biology; REM-SLEEP; Life Sciences & Biomedicine - Other Topics
• Research Categories: Engineering, Biomedical

Abstract

Oscillatory brain activity reflects different internal brain states including neurons’ excitatory state and synchrony among neurons. However, characterizing these states is complicated by the fact that different oscillations are often coupled, such as gamma oscillations nested in theta in the hippocampus, and changes in coupling are thought to reflect distinct states. Here, we describe a new method to separate single oscillatory cycles into distinct states based on frequency and phase coupling. Using this method, we identified four theta-gamma coupling states in rat hippocampal CA1. These states differed in abundance across behaviors, phase synchrony with other hippocampal subregions, and neural coding properties suggesting that these states are functionally distinct. We captured cycle-to-cycle changes in oscillatory coupling states and found frequent switching between theta-gamma states showing that the hippocampus rapidly shifts between different functional states. This method provides a new approach to investigate oscillatory brain dynamics broadly.